Double running suture provides faster visual rehabilitation in penetrating keratoplasty surgery

Residual astigmatism following perforating keratoplasty represents an important limitation of this procedure. In fact, while advances in surgical techniques, materials and instruments led to a considerable improvement in anatomical results, especially in terms corneal graft transparency over time, on the other hand, high or irregular post-operative astigmatism may bring poor and unsatisfactory functional results in a not negligible percentage of patients.

Factors affecting postoperative astigmatism are represented mainly by healing processes and the adopted suturing technique. Over the years, several suture techniques have been proposed for this procedure. This has led to a search for the best technique in terms of risk-benefit ratio. Currently, the mainly used techniques are represented by interrupted suture (INT), single running suture (SRS) and double running sutures (DRS).

The purpose of the prospective study by Nuzzi et al was to evaluate the effects of different suture techniques in penetrating keratoplasty surgery, in order to identify the most effective in reducing post-operative astigmatism. The results showed that at 12 months after surgery, the double running suture technique is the one associated with minor corneal astigmatism if compared with interrupted sutures or single running suture.

Authors analysed data from patients who underwent penetrating keratoplasty for different indications. All interventions were performed by the same surgeon. Patients were subjected to a follow-up of at least 12 months after surgery, during which astigmatism (assessed by keratometry, topography and refraction) best-corrected visual acuity (BCVA) and complications were evaluated. A total of 100 eyes from 100 patients were included and were randomly assigned to five different groups, each one featuring a different suturing technique: interrupted (INT), single running (SRS), double running with two 10–0 sutures (DRS), double running antitorque with two 10–0 sutures (DRSa), double running with both 10–0 and 11–0 sutures (DRS with 11–0).

There was a statistically significant difference in astigmatism after surgery between the double running sutures groups and the others with different techniques. However, there was no statistically significant difference between the INT and the SRS group; moreover, there was no statistically significant difference between the different groups with double running sutures (DRS, DRSa, DRS with 11–0). There was no statistically significant difference in BCVA values among the five groups. The wound leak rate was 10% in the INT group, 5.3% in the SRS group and 0% in all groups with double running sutures.

The results show that at 12 months after surgery, the double running suture technique is the one associated with minor corneal astigmatism if compared with interrupted sutures or single running suture, regardless of whether two 10–0 nylon sutures are used, or one of them is a 11–0 suture or whether they are placed in antitorque mode. Furthermore, the double running technique, unlike the alternative techniques, was associated with a lower rate of postoperative complications, with no cases of wound leak or dehiscence. This phenomenon can be explained by a greater need of postoperative suture manipulation in the INT and SRS groups, while sutures in the DRS technique tend to be adjusted less, or not at all, especially in case of a double continuous suture with both 10–0 and 11–0 nylon threads.

Although there is no agreement in the literature on which suture technique is the one associated with minor astigmatism, it is widely accepted that double running sutures allow faster rehabilitation of visual function after penetrating keratoplasty. In fact, it was possible to remove one of the two sutures after just 2–3 months after surgery, leaving the second one in place. Moreover, especially in case of 11–0 suture application, the remaining thread will begin to spontaneously dissolve at 15–20 months. Additionally, DRS is a safer technique as it comes with a lower risk of complications.

In conclusion, the results of study show that in penetrating keratoplasty surgery the double running suture technique can provide better outcomes as it is associated with minor postoperative astigmatism, leads to faster visual rehabilitation and has a lower complication rate if compared with techniques featuring single running and interrupted sutures. There are no differences in terms of postoperative astigmatism or complication rates between the different double running suture techniques examined.

Source: Nuzzi et al; Clinical Ophthalmology 2022:16

https://doi.org/10.2147/OPTH.S355538